This invention relates to a method of making packages by means of a packaging machine. More particularly, this invention relates to a method of making packages by increasing the volume density of the articles that are to be packaged.
Packages of articles which are easily breakable and low in volume density, such as potato chips, are difficult to handle efficiently because a large amount of package-making material is required to package them and the costs of their transportation are high. In view of this problem, U.S. Pat. No. 5,540,035, for example, disclosed a method of shaking the articles which have been dropped into a bag before it is sealed such that the volume of the batch of articles to be sealed in is reduced. If this technology is applied to a large-scale packaging machine adapted to package twice or three times more articles in each bag than a packaging machine of a normal size, however, it is not possible to effectively increase the volume density of articles inside the bag, and the packaging speed is adversely affected significantly.
It is therefore an object of this invention in view of this problem of the prior art technology to provide an improved method of producing large packages while efficiently increasing the volume density of the articles.
A packaging method embodying this invention, with which the above and other objects can be accomplished, may be characterized as comprising the steps of clamping a tubularly formed bag-making film with a shaking mechanism (herein referred to as the shaker), dropping a batch of articles into this film while it is in this clamped condition, and shaking this batch of articles by activating the shaker to thereby increase its volume density. This is done once or repeated any number of times, and after articles of the final batch are dropped into the film, the clamped condition of the film is released and the articles are dropped further downward to the bottom of the bag being made. The tubularly formed film is thereafter sealed transversely above the batches of articles which have been dropped to close the bag.
The user may use an input device to input various packaging conditions such as the length of each bag to be made and the packaging speed (that is, the number of packages to be produced per unit time). A packaging machine according to this invention includes a control unit which determines whether the film should be transported intermittently or continuously by comparing at least one of the inputted packaging conditions and a preliminarily stored value such as a packaging speed. The steps described above are carried out if the control unit concludes that the film should be transported in an intermittent mode. If the control unit concludes that the film should be transported in a continuous mode, the film is pulled down in a continuous motion without subjected to the shaking by the shaker.